1. Field of the Invention
The present invention relates to a data recovery circuit, and more particularly, to a data recovery circuit for use in a high-frequency DVI receiving system.
2. Description of the Related Art
DVI (Digital Visual Interface) is a digital display interface standard established by several PC and graphic card manufacturers. Thanks to the high speed and the excellent display quality of the DVI transmission system, it is foreseeable that DVI interface will become a widely used standard interface for image display in the near future.
In a data transmission structure of a display system configured with DVI standard, three 8-bit digital image signals respectively for the three primary colors of red, green and blue generated by a graphic card in a computer host are sent to a DVI encoder for encoding into 10-bit DVI image signals. Subsequently, these 10-bit DVI image signals are converted by a DVI transmitter into differential serial image signals and transmitted by a DVI transmission cable to a DVI receiver in a display device.
In a known DVI receiver, the received differential serial image signals are sent to a 1:2 demultiplexer for performing a serial-to-parallel conversion to generate 2-bit parallel signals for subsequent data recovery process. Then, 10-bit DVI image signals are recovered from the 2-bit parallel signals and thereafter decoded by a DVI decoder into 8-bit digital image signals to be displayed on a display panel.
However, according to the DVI standard, the data transmission is implemented though an extremely high frequency. For example, the differential serial image signal is transmitted at a rate of 1.6 GHz, and thus the 2-bit parallel signal converted from the differential serial image signal is transmitted at 800 MHz, which is still high. Since it is difficult to generate a clock signal with such a high frequency and is very complicated to process a high-frequency data signal, there is a need to develop a data recovery circuit that is operable at a lower frequency.